Manufacture of artificial materials



A Oct. 21, 1941. us 2,259,518

MANUFACTURE OF ARTIFICIAL MATERIALS Filed Oct. 10, 1956 ALL ROLLERS OF EACH SET ARE POSITIVELY DRIVEN HENRY DREYFUS iNVENTM Patented Oct. 21, 1941 UNITED STATES PATENT OFFICE 2,259,518 a i MAN UFACTURE F ARTIFICIAL MATERIALS Henry Dreyfus, London, England Application October 10, 1926, Serial No. 105,071

In Great Britain October 28, 1935 2 Claims.

This invention relates to improvements in the manufacture of artificial materials, and particularly to improvements in processes and apparatus for the manufacture of artificial filaments, yarns and other materials by wet spinning processes.

Wet spinning processes for the manufacture ofartificial filaments and other materials having a basis of organic derivatives of cellulose have been described in U. S. Patent No. 1,465,994, which employs coagulating baths containing thiocyanates, and in U. S. Patent No. 1,467,493, which describes the use of aqueous baths containingacetone, diacetone alcohol, and other 501- vents and latent solvents for cellulose acetate. Again, U. S. applications S. Nos. 402,785 filed October 26, 1929, and 418,414, filed January 3, 1930, and British Patents Nos. 340,326 and 340,-

437, describe the use of coagulating baths or after-treatment baths containing high concentrations of solvents or non-solvent plasticisers for cellulose derivatives, while U. S. application S. No. 469,622 filed July 21, 1930, is concerned with the coagulation of artificial filaments, ribbons and other products, or their after-treatment continuously with their production by wet or dry spinning processes, in baths which contain high concentrations of solvents and salts orother substances adapted to reduce the solubility of the solvent in the non-solvent medium. U. S application S. No. 601,043 filed March 24, 1932, describes the production of artificial filaments,

threads and other products by wet spinning processes in which they are coagulated or aftertreated with baths containing high concentrations of glycol monoacetate orother lower all-- phatic acid esters of dior poly-hydric alcohols, other than monoor di-acetin, or their partial ethers.

Whereas it is common practice in the producf tion of artificial filaments and similar products by dry-spinning processes to carry out the manufacture at a spinning speed of, for example, 300 metres per minute or more, in the production of artificial filaments and similar products by wet spinning processes, for example as described in the above specifications, it has not been prac-; ticable to obtain spinning speeds greater than about 60 up to 100 metres per minute at the most, Thus British Patent No. spinning artificial filaments into an aqueous eoagulating bath and passing them round a feed roller driven at a peripheral-speed of 50 metres per minute, while U. S. application S. No. 469,622 filed July 21, 1930, in Example 1, refers to per ipheral speeds of 25 to 50 up to 100 metres per min ute.

It has now been discovered that considerably greater spinning speeds may be attained in wet spinning processes by passing the artificial filasmsv desc ibe ments or other materials in contact with a plurality of rollers or other forwarding devices during their travel from the shaping device to the takeup device. By this means artificial filaments may, for example, be wet spun at a speed of -200 metres per minute or more. The artificial filaments or other materials may contact with the forwarding devices during their travel through the coagulating bath or after emerging therefrom, for example, while'they are passing through an after-treatment bath containing a softening medium or while passing through the air. In this latter case the materials are preferably sprayed with a softening medium during their travel through the air. If desired the filaments or other materials may contact with one or more forwarding devices during their passage through the coagulating medium, and with one or more .forwarding devices after emerging from the coagulatiiig medium and before reaching the take-up device. 'I'he'concentration of the softening nedium through which the materials pass or with which they are sprayed may change either gradually or abruptly along their path of travel. Thus filaments emerging from a coagulating bath having a high softening power, e. g. a 55-60% aqueousjsolution of diacetone alcohol, may be sprayed at intervals, e. g. while passing in contact with the forwarding devices, with solutions of diacetone alcohol of progressively decreasing concentration and finally with Water in 'order to wash them. They may betaken up in a spinning box and dried in cake form or be dried by passage through a heated chamber and wound or twisted and wound 9 a cap spinning machine or other take-up device.

A forwarding device which has been found to yield very good results consists of a set of three rollers, the second roller of each set being positioned at a level above that of the first and third rollers so that the filaments or other products pass under the first roller, up and over the second roller, and then' down and underneath the third roller. All three rollers of each set may be positioned below the surface of the coagulating or after-treatment medium, or the second roller may be above the surface, in which case the products are preferably sprayed with the medium while out of contact with the bath.

A similar forwarding device, which also yields very good results, consists of a set of three roll,- ers, the second roller of the set being below the level .of the first and third. All three rollers m be b low t e s riace of e medium or J the second only may be below, in which case the products are preferably sprayed with the mewhile they are out of contact with the a general, when rollers are employed which are not immersed in a coagulating or after-treat f An example shaping device to the bobbinso'r'other' take-up devices, and the speeds of the sets. ofirollers. or other forwarding devices may be, controlled so that e. g. the yarn or other product is. stretched during the whole of its travel, or so "thate. g: over portions of its travel no stretch is effected, the length. of the product being maintained constant or shrinkagabeing'allowed to takeplace. Moreover the invention renders'it possibleto reduce. thejjt'ension due to friction between the liq-' uid bath and filaments; e. g. by means of -the setsiofjthree rollers described above;

' The proc'ess and apparatus of vention 'are' applicable broadly to the production of.,artificial yarns," foils 'and other products by wetjspinning' processes, for'example the processes, described in the above specificaations, and particularlytoprocessesin which coagulation of the products is effected in the presence of a high concentration of a solvent or other softening agentio'r the 'baseoftheproducts', e. g. a concentration of at least FIOI'OI %.j Preferably an aqueous coagulatingor after-treatment medium is employed. "Softening iagents which'may be employedare acetone; methylene ethylene ether, dioxane" andother' volatile liquids, though pref' erably ethyl -lactate, diacetone alcohol, glycol monoacetata] methyl glycol monoacetate and otherliquids of low'volatility are employed. The bath may be covered with a relatively non-volatile liquid which is immiscible with the bath, for example anoil, in order to lubricate the products and/or toprevent evaporation of softening agent. or diluent, particularly when 'a volatile softening agent is employed, as described in 11-8. application 3. No. 690,122jjfiled September 19,, l933.

.of' a'wet spinning apparatus comprisinga plurality of forwardling devices accord ing to the present. invention is illustrated in the accompanying drawing, which shows a sectional elevation of' a wet spinning device, an aftertreatment device and a take-up devicei f'Thei apparatus comprises a vessel I for coagulating medium which contains a jet 2 connected through'a'candlefilte'r 3 with a header 'or other supply of ,fspinning'solution (not shown); T0- wards the end ofthe vessel remote from the jet is provided with a set 6 of three positively driven rollers arranged at the vertices of a triangle, and above the set of rollers is arranged. a spray'device. 5. Atthe end'of the vessel l is a vessel H in which are mounted two sets of positively driven rollers 8. and II], the rollers of eachset being arranged at the' vertices of a triangle. Above the sets'of rollers are provided spray devices 1 and 9. An overflow l2 is provided in the end of the vessel II at such a height that the liquid level in the vessel ii. is maintained above thetop of. the bottom roller of feach set.v The apparatus also comprises a draw roller [3, aguide l4 and a' spinnin'g box l iflfor taking up the yarn.. 7 J In operation ,the bundle of' filaments 4 issuing from the jet '2 into a suitable coagulating medium,.for example a 45 to aqueous solution of ethyl lactate, passes round the set of rollthe present iners 5 whereby they are sprayed with a suitable softening medium while passing over the middle roller of the set. From these rollers they proceed round the sets of rollers 8 and H) where they are sprayed by means of the spray I and 9 and then proceed to the draw roller [3 after which they pass round the guide [4 and are taken up in the spinning box l5. The sets of rollers 6, 8 and I0 "and the draw roller I3 may be rotated at such speeds that the materials are drawn down between the jet and the set of rollers 6, between 1 .each set'of rollers and between the set of rollers l0 and the draw roller l3, or if desired the speeds of the rollers may be such that no stretching takes place during some portion of the travel of thematerials from the jet to the draw froller.

The" softening -medium employed for spraying m ay alsobe" a Flo-50% ethyl lactate solution, or

media of decreasing concentration in'a'y be -'em-- ployed in' passing from the spray 5 to the spray 9, so that a gradual decrease in the plasticity of the materials is effected. For example the materials maybe sprayed at I witha 35-40% ethyl lactate solution and at 9 with oneof 25-30%.

While the present invention is of particularimportance in relation tofthe manufactureof artificial materials having a basisof cellulose acetateit niay al'so be employed in the manu-' facture of artificial materials having a basis of cellulose formate, propionate, butyrate, nitroacetate, acetate-propionate, :and'other esters and mixedesters of cellulose, methyl, ethyl, butyl and benzyl celluloses and other cellulose ethers and mixed ethers, and ethyl cellulose acetate and oxyethyl 1 cellulose acetate.

Moreover, it may also be "employed in the manufacture by wet spinning processes of artificial materials having a basis of other suitable substances, for example in the manufacture of regenerated cellulose materials by the viscose process. i.

The term forwarding device is employed in the description and claims of the present application to denote a device which imparts a forward 'movement'f to the materials;

Having described invention what I desire to secure by Letters Patent is:

1 1-.- In wet spinning apparatus tion'of artificial filaments, yarns, foils, films and similar materials, a vessel for containing coagu lating liquidfa shaping device through which a spinning solution is extruded into the vessel con'- taining the coagulating liquid, and a plurality. of

forwarding devices at least one of'whichis contained substantially within the vessel containing the coagulating liquid,.each ofwhich comprises a 'setof. three rollers arrangedat .thevertices of 'a'triangle, each o f the rollers of eachset' being positively driven.

2'. Inwetspinningapparatus for the tion of artificial. filaments, yarns, 'foils", .filmsl and similar materials, a'vessel for containing coagulating liquid, a shaping device through which 'a' spinning solution is extruded into thevessel con tainingthefcoagulating liquid;and a plurality or. forwarding devices at least oneof whichiis .con-' tainedsubstantiallywithin the vessel containing the-coagulating liquid, each of which comprises aset of three'ro'llers arranged at'the 'vertices of a triangle-cachet the'rollers of each set-being positively driven at' the same speed and-ea chof the stsofrollers beingadapted to be driven at difierent speeds.

for the produc- 

